QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ferguson, R. A. Articles by Sargeant, A. J. Search for Related Content PubMed PubMed Citation Articles by Ferguson, R. A. Articles by Sargeant, A. J.

Effect of muscle temperature on rate of oxygen uptake during exercise in humans at different contraction frequencies

Richard A. Ferguson^1,*, Derek Ball^1, and Anthony J. Sargeant^1,2

¹ Centre for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Hassall Road, Alsage, Alsager ST7 2HL, UK
² Institute for Fundamental and Clinical Human Movement Sciences, Vrije University, Amsterdam, The Netherlands
^* Present address: Applied Physiology Group, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, Southbrae Drive, Glasgow G13 1PP, UK
Present address: Biomedical Sciences, University Medical School, Foresterhill, Aberdeen, AB25 2ZD, UK

View larger version (13K): [in a new window]   Fig. 1. O2/power output relationship during the incremental multistage exercise test at contraction frequencies of 60 revs min-1 (filled squares) and 120 revs min-1 (open squares), respectively. Regression coefficients were 0.995 in both instances. Values are means ± S.E.M. (N=6).

View larger version (13K): [in a new window]   Fig. 2. Continuous measurement of pulmonary O2 in one subject during exercise at 60 (A) and 120 revs min-1 (B) under conditions of normal (filled circles) and increased (open circles) muscle temperature. Data points are breath-by-breath values averaged over 10 s.

View larger version (13K): [in a new window]   Fig. 3. Pulmonary O2 during exercise at 60 (A) and 120 revs min-1 (B) under conditions of normal (filled circles) and increased (open circles) muscle temperature. Data points are breath-by-breath values averaged over 1 min. Values are means ± S.E.M. (N=6). Difference (P<0.05) between normal and elevated muscle temperature are indicated by an asterisk.

View larger version (13K): [in a new window]   Fig. 4. Concentration of blood lactate before hot water immersion (Pre), immediately before exercise (Rest) and post-exercise at 60 (A) and 120 revs min-1 (B) under conditions of normal (filled circles) and increased (open circles) muscle temperature. Values are means ± S.E.M. (N=6). Difference (P<0.05) between normal and elevated muscle temperature are indicated by an asterisk. Note that the data points at Pre and Rest are superimposed.

View larger version (13K): [in a new window]   Fig. 5. A schematic representation of the qualitative changes that, on theoretical grounds, might be expected of the efficiency/velocity relationship consequent upon an increase in muscle temperature. In the illustration, the solid line shows the efficiency/velocity relationship for a muscle that has an optimum velocity for maximum efficiency close to 60 revs min-1 under normal conditions. The dashed line indicates the expected rightward shift consequent upon an increase in muscle temperature. Thus, increasing muscle temperature at 60 revs min-1 results in a decrease in efficiency from point a to b. In contrast, at a higher movement frequency (120 revs min-1), efficiency increases from to c to d as a result of the rightward shift in the relationship.